<!DOCTYPE html>
<script src="../../../resources/js-test.js"></script>
<style>
fieldset:disabled { background-color: green }
fieldset + div { color: pink }
</style>
<fieldset id="fieldset">
    <legend></legend>
    <label for="field"></label>
    <input type="text" name="field" id="field">
    <div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>
</fieldset>
<div>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
</div>
<script>
description("Use descendant invalidation set for :disabled fieldset.")

var transparent = "rgba(0, 0, 0, 0)";
var green = "rgb(0, 128, 0)";

shouldBe("getComputedStyle(fieldset, '').backgroundColor", "transparent");

fieldset.offsetTop; // Force recalc.
fieldset.disabled = true;

if (window.internals) {
    // There are still instances of SubtreeStyleChange left when updating
    // disabled state. This count should become lower.
    shouldBe("internals.updateStyleAndReturnAffectedElementCount()", "2");
}

shouldBe("getComputedStyle(fieldset, '').backgroundColor", "green");
</script>
